<script setup>
import { ref, watch } from "vue";
import { useMouseInElement } from "@vueuse/core";

// props 适配图片列表
defineProps({
  imageList: {
    type: Array,
    default: () => [],
  },
});
// 图片列表
// const imageList = [
//   "https://yanxuan-item.nosdn.127.net/d917c92e663c5ed0bb577c7ded73e4ec.png",
//   "https://yanxuan-item.nosdn.127.net/e801b9572f0b0c02a52952b01adab967.jpg",
//   "https://yanxuan-item.nosdn.127.net/b52c447ad472d51adbdde1a83f550ac2.jpg",
//   "https://yanxuan-item.nosdn.127.net/f93243224dc37674dfca5874fe089c60.jpg",
//   "https://yanxuan-item.nosdn.127.net/f881cfe7de9a576aaeea6ee0d1d24823.jpg",
// ];

//1 鼠标移入切换显示大图
const imgIndex = ref(0);
const imgHandler = (i) => {
  imgIndex.value = i;
};
//2 鼠标移入小图显示激活状态

// 3 显示大图放大镜效果,使用vueUse 的函数 useMouseInElement
const target = ref(null);
const { elementX, elementY, isOutside } = useMouseInElement(target);
// console.log(elementX, elementY, isOutside);
// 控制滑块跟随鼠标移动（监听elementX/Y变化，一旦监听到变化重新计算left/top）
const left = ref(0);
const top = ref(0);

const positionX = ref(0);
const positionY = ref(0);

watch([elementX, elementY], () => {
  // console.log("x/y变化了");
  // 优化下，如果鼠标不再大图区域内就不需要执行下面的代码了
  if (isOutside.value) return;
  // console.log("执行后续代码");
  // 先判断横向移动
  if (elementX.value > 100 && elementX.value < 300)
    left.value = elementX.value - 100;
  // 再判断纵向移动
  if (elementY.value > 100 && elementY.value < 300)
    top.value = elementY.value - 100;

  // 最后判断临界值
  if (elementX.value > 300) left.value = 200;
  if (elementX.value < 100) left.value = 0;

  if (elementY.value > 300) top.value = 200;
  if (elementY.value < 100) top.value = 0;

  // 控制显示大图
  positionX.value = -left.value * 2;
  positionY.value = -top.value * 2;
});

// 判断鼠标是否在大图区域内
</script>


<template>
  <div class="goods-image">
    <!-- 左侧大图-->
    <div class="middle" ref="target">
      <img :src="imageList[imgIndex]" alt="" />
      <!-- 蒙层小滑块 -->
      <div
        class="layer"
        v-show="!isOutside"
        :style="{ left: `${left}px`, top: `${top}px` }"
      ></div>
    </div>
    <!-- 小图列表 -->
    <ul class="small">
      <li
        v-for="(img, i) in imageList"
        @mouseenter="imgHandler(i)"
        :key="i"
        :class="{ active: i === imgIndex }"
      >
        <img :src="img" alt="" />
      </li>
    </ul>
    <!-- 放大镜大图 -->
    <div
      class="large"
      :style="[
        {
          backgroundImage: `url(${imageList[imgIndex]})`,
          backgroundPositionX: `${positionX}px`,
          backgroundPositionY: `${positionY}px`,
        },
      ]"
      v-show="!isOutside"
    ></div>
  </div>
</template>

<style scoped lang="scss">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;

  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
  }

  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    z-index: 500;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    // 背景图:盒子的大小 = 2:1  将来控制背景图的移动来实现放大的效果查看 background-position
    background-size: 800px 800px;
    background-color: #f8f8f8;
  }

  .layer {
    width: 200px;
    height: 200px;
    background: rgba(0, 0, 0, 0.2);
    // 绝对定位 然后跟随咱们鼠标控制left和top属性就可以让滑块移动起来
    left: 0;
    top: 0;
    position: absolute;
  }

  .small {
    width: 80px;

    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;

      &:hover,
      &.active {
        border: 2px solid $xtxColor;
      }
    }
  }
}
</style>